1. Field of the Invention
In one of its aspects, the present invention relates to a foam composite material, preferably in the form of a seat. In another of its aspects, the present invention relates to a process for producing a foam composite material, preferably in the form of a seat.
2. Description of the Prior Art
Passenger seats in vehicles, such as automobiles, are typically fabricated from a foam (usually polyurethane) material which is molded into the desired shape and covered with an appropriate trim cover. The foamed material is selected to provide passenger comfort by providing a resilient seat and the trim cover is selected to provide the desired aesthetic properties.
To meet desired safety standards, passenger seats in vehicles such as automobiles now often provide anti-"submarine" properties. Submarining is the term used to describe the tendency of the pelvis of a seated passenger to move forward and down during a collision. When the passenger is wearing a shoulder harness or lap type seatbelt, this tendency can result in the seatbelt strangling the passenger with potentially fatal consequences. Accordingly, it is known in the art to design passenger seats with anti-submarine properties. These properties may be provided by rigid or semi-rigid members embedded in the seat and which provide additional pelvic support to the passenger during a collision. To function properly, these members cannot move and thus, must be fixed (directly or indirectly) to the vehicle.
It is also known in the art that, while the resiliency of the foamed material in the seat provides passenger comfort, it does not provide the necessary structural strength for the seat. This necessitates additional reinforcement of the seat to provide the degree of structural strength required to ensure proper mounting of the seat within the vehicle and proper support of anti-submarine elements. Accordingly, prior art vehicular seats typically include a perimeter frame of metal which strengthens the seat. Further, support rails are typically mounted across the metal frame to stiffen the frame and to provide a suitable attachment point for the means used to anchor the seat to the vehicle. Conventionally, the metal frame and/or support rails are substantially completely embedded in the foam material when the seat is molded. In many cases, the metal frame will further comprise a plurality of apertures or other means for attaching a trim cover to the seat.
Of course, the requirement for such a perimeter metal frame and for support rails adds to the cost of manufacturing the seat and, more importantly, adds to the weight of the seat and the overall weight of the vehicle in which it is installed. This added weight increases both the cost of shipping the seat to the vehicle manufacturer and the eventual lifetime operating expense for the vehicle. Finally, the presence of metal frame and support rails or other components in the seat hampers the eventual recycling of the seat materials which is becoming increasingly important in today's environmentally concerned marketplace.
U.S. Pat. Nos. 5,400,490 [Burchi] and 5,542,747 [Burchi], issued Mar. 28, 1995 and Aug. 6, 1996, respectively, the contents of each of which are hereby incorporated by reference, describe a passenger seat comprising a frame element molded from relatively high density, rigid foam; vehicle anchorage means connected to the frame element; and a seat body comprising a resilient material fixed with respect to the frame element. The provision of a frame element molded from relatively high density, rigid foam obviates the need for a conventional metal frame. The '490 and '747 patents also teach application of a trim cover to passenger seat. The trim cover may be attached using push pins or a combination of bottom flaps (see FIGS. 3 and 9 in the '490 and '747 patents) with conventional mechanical attachment means (e.g., Velcro.TM., J-retainers or push pins).
While the invention taught in the '490 and '747 patents represents a significant advance in the art, there is still room for improvement. One such area is in the attachment of the trim cover to the passenger seat. Specifically, in certain cases, for a number of reasons, it can be advantageous to avoid the use of push pins to attach the trim cover as taught in the '490 and '747 patents. First, the trim cover may have to be pre-drilled or otherwise pretreated to permit penetration of the push pins, involving additional manufacturing cost (this is especially true for trim covers made of an impermeable material such as vinyl or leather). Second, a large number of push pins is required to adequately secure the trim cover to the relatively high density, rigid foam frame, involving additional manufacturing cost, both in materials and labour. Third, the trim cover must be correctly positioned over the resilient material and the relatively high density, rigid foam frame independently of placement of the push pins, increasing the likelihood for improper placement and attachment of the trim cover.
One area of improvement is disclosed in copending U.S. patent application Ser. Nos. 08/706,427, 08/706,431, 08/706,432 and 08/706,433 (each naming Burchi et al. as applicants), each filed on Aug. 30, 1996 and the contents of each of which is hereby incorporated by reference. Specifically, these copending applications set forth an improved system for connecting the trim cover to the rigid foam frame element, and a mold and process for production of an improved seat system.
One area where further improvement would be desirable in this art is in the capital requirements needed and efficiency possible in producing the seat specifically illustrated in the '490 and '747 patents. In particular, both the rigid foam frame element and the resilient foam are molded in the specific embodiment illustrated in the '490 and '747 patents. As will be appreciated by those of skill in the art, if one were to produce this seat on a commercial scale, two molds would be required for each seat--i.e., one mold to produce the rigid foam frame element and one mold in which: (i) the rigid foam frame element is placed, and (ii) the resilient foam is expanded, to produce the final foam product. This requirement results in a significant increase in the capital requirements need two purchase additional molds. Further, the need to conduct two independent molding operations results in a 50% reduction in manufacturing efficiency (i.e., compared to a single molding operation in which a metal frame is embedded in the foam).
Thus, notwithstanding the above-mentioned advances in the art, there continues to remain room for improvement.
Therefore, it would be desirable to have a process for producing a foam composite material, such as the seat specifically illustrated in the '490 and '747 patents which overcomes the need for the use of two molds to produce the final foam product.